Lepton flavour violation in constrained MSSM-seesaw models

TL;DR

This paper predicts lepton flavour violating decays in a SUSY-seesaw model, analyzing various tau and muon decay channels, comparing predictions with experimental bounds, and highlighting the most promising processes for future detection.

Contribution

It provides detailed predictions for LFV tau and muon decays within a constrained MSSM-seesaw framework, including hadronisation effects and different SUSY-breaking scenarios.

Findings

Certain LFV processes are within reach of future experiments.

Universal and non-universal SUSY-breaking scenarios yield different LFV predictions.

Some decay channels show higher sensitivity to model parameters.

Abstract

We calculate the predictions for lepton flavour violating (LFV) tau and muon decays, $l_j \to l_i \gamma$, $l_j \to 3 l_i$, $\mu-e$ conversion in nuclei and LFV semileptonic tau decays $\tau \to \mu PP$ with $PP= \pi^+\pi^-, \pi^0\pi^0, K^+K^-, K^0 {\bar K}^0$ $\tau \to \mu P$ with $P=\pi^0, \eta, \eta'$ and $\tau \to \mu V$ with $V = \rho^0, \phi$, performing the hadronisation of quark bilinears within the chiral framework. We work within a SUSY-seesaw context where the particle content of the Minimal Supersymmetric Standard Model is extended by three right-handed neutrinos plus their corresponding SUSY partners, and where a seesaw mechanism for neutrino mass generation is implemented. Two different scenarios with either universal or non-universal soft supersymmetry breaking Higgs masses at the gauge coupling unification scale are considered. After comparing the predictions with present experimental bounds and future sensitivities, the most promising processes are particularly emphasised.